It is known that basic and cationic dyes are water soluble in their conventional salified form, and that their isolation from the mother liquors of the reaction occurs, in particular in the case of dyes having a high solubility in water, through chlorzincate and/or salting with NaCl. The washing is always carried out with brine, wherefore the dyes always contain a more or less high percentage of NaCl.
The term "basic dyes" means the dyes described in Colour Index 3rd ed. A.A.T.C.C., 1st Vol., page 1507 et seq., under the generic name "C.I. Basic Dyes". The term "basic optical brighteners" means the one described in the 2nd vol., page 2743 et seq., under the generic name "C.I. Fluorescent Brighteners" and characterized by cationic ionicity.
There are few known and applicable lacquers of basic and cationic dyes owing to the difficulty of obtaining water-insoluble salts or complexes, which are capable of retaining unchanged the brightness of the starting dyes and which possess good general stabilities and retain unaltered or even improve the fastness to light of the starting dye on certain substrata, in which the starting dye has low stabilities to sunlight, for example substrata other than polyacrylonitrile fibres.
Lacquers having a good fastness to sunlight and good general stabilities such as phosphomolybdic, phosphotungstomolybdic lacquers of basic and cationic dyes are actually known.
It is also known that the borates of cationic dyes described in Belgian Pat. No. 747,583, besides requiring a complicated synthesis and providing low yields, are more soluble in water than the ones salified with the inorganic anions usually obtained from the conventional syntheses.
It is known too that certain anionic complexes of boric acid and the salts thereof possess a better solubility in water than the starting products, for example the water-solubility of calcium gluconate is increased up to about ten times by complexing with boric acid (Merck Index, 7th Ed. page 193), wherefore it could not be expected, from these 2 examples, to obtain water-insoluble salts from anionic esters of boric acid with basic dyes.